Various studies showing that the differentiation of stem cells is promoted using an electromagnetic field have been reported. Fregni et al. reported that various types of electric and electromagnetic field stimulation relieve pain from chronic neuralgia caused by spinal damage (Non-patent Document 1), and Ahmadian S. et al. reported that an increase in the collagen of mouse skin is observed when the skin of mice is irradiated daily with a frequency of 25 Hz and an intensity of 2 mT for 2.5 hours (Non-patent Document 2).
Also, studies on osteogenesis using an electromagnetic field have been reported. Ceccarelli et al. reported that the osteogenic differentiation of various mesenchymal stem cells is promoted by an electromagnetic field having a frequency of 75 Hz and an intensity of 2 mT (Non-patent Document 3), Sun et al. reported that, when bone marrow-derived mesenchymal stem cells are cultured under an electromagnetic field having a frequency of 15 Hz and an intensity of 1.8 mT, the expression of alkaline phosphatase (ALP) and a bone morphogenetic protein (BMP-2) is promoted to stimulate the differentiation into osteocytes, and Schwartz et al. reported that the osteogenic differentiation of mesenchymal stem cells is promoted by an electromagnetic field having a frequency of 15 Hz and an intensity of 1.6 mT. The study on the promotion of osteogenic differentiation using such an electromagnetic field uses an electromagnetic field having a frequency of 7.5 to 15 Hz and an intensity of 0.1 to 5 mT (Non-patent Document 4).
In recent years, as therapeutic methods using stem cells to treat neurological diseases such as Alzheimer's disease, depression, Parkinson's disease, cerebral infarction, cerebral hemorrhage, damaged spinal cord and the like have emerged, methods using electrical stimulation in research conducted to promote the differentiation into nerve cells have also been reported. As the neurotherapeutic techniques known in the related art, there is a device configured to apply energy with a low frequency of approximately 10 Hz or less to brain tissue, characterized in that, after electrodes are implanted into a patient's brain, electrical stimulation is directly applied to the electrodes to induce a magnetic field using a flow of electricity (Patent Document 1). Zheng developed a method of applying magnetic stimulation to the central nervous system as a technique in which high frequencies or a plurality of frequency components are combined and used to improve brain functions (Patent Document 2), and Riken developed a technique of treating embryonic stem cells with electric pulses to prepare nerve cells (Patent Document 3). Gliner et al. developed a technique of treating cells with electric pulses to prepare nerve cells (Patent Document 4). The above-described methods have limits on clinical applications since an additional surgical operation in which electrodes are implanted using a method of directly implanting electrodes should be conducted, thereby inflicting pain on patients and increasing the likelihood of embryonic stem cells forming tumors. Therefore, there is a demand for novel technology for differentiating mesenchymal stem cells and adult stem cells into nerve cells using a non-invasive method rather than a chemical method. Because of such a demand, the present inventors have conducted research on the mesenchymal stem cells and the adult stem cells as cell therapy products for treating various neuron-associated diseases. Therefore, the present invention has been completed based on these facts.